Marine edifices are suitable for colonization by hardground animal species. This can be observed especially clearly in areas marked by the absence of natural colonization structures, such as in the softground regions of the southern North Sea. The surfaces of the edifices, such as pylons of wind power plants, are here used as colonizing surfaces by the reef animals. In order to augment such reef animals, various types of so-called “artificial reefs” are assembled or submerged into the sea worldwide. Net fishing with draw nets and beam trawl nets is difficult or impossible in the immediate proximity to marine edifices. In addition, it is not sustainable, and can quickly lead to overfishing. Marine hardground animals, such as lobsters, crabs, snails, mollusks and several types of fish, have previously been caught in inaccessible areas or not readily fishable sea floors using baited traps, such as lobster creels. However, baited traps have to be brought in again a short time after set up. Therefore, they cannot be left on site for an indeterminate time, for example during inclement weather, without jeopardizing the catch. In addition, such traps may get caught on parts of edifices or be shifted into impermissible positions on foundation structures on the sea floor as the result of currents and wave dynamics. As a result, they cannot be placed precisely in the most favorable positions on the foundation structures. In addition, such traps themselves do not provide an attractive colonization habitat. Further, the traps must be specially marked with lines and buoys, which can tear away when used on offshore edifices or lead to other problems.
U.S. Pat. No. 6,186,702 describes a habitat and trapping device that can be used for lobsters, for example, a so called “artificial reef”, which is simply released onto the sea floor and retrieved again when necessary. U.S. Pat. No. 5,596,947 describes larger holding boxes, which are lowered from inclined rope guides from a special platform and hauled in again. Vertically submergible stacked habitat and harvesting boxes are described in WO 2004/075633 A1.
DE 203 10 089 U1 describes a netting array in the area of a wind power plant pylon for colonizing and harvesting hardground animals, which can be lowered and retrieved by means of a cable winch as the lifting device. The netting array is here designed as a basket that is relatively unattractive to the hardground animals and which is simply lowered into the water or placed on the sea floor. This netting array is positioned as desired by means of a rail system, which partially or completely horizontally envelops the pylon in a radial plane, and has hooked into it a framework for the cable winch. Therefore, a horizontally running rail system is known for positioning a netting array as desired around the periphery of the pylon. The netting array is lowered and retrieved exclusively via the cable winch, unguided in the free sea currents, thereby creating a strong dependency here. The settling netting array can here threateningly get into the operating area of the edifice or any service facilities on hand. The net fishing array cannot be precisely positioned. Additionally, U.S. 2006/0170221 A1 for the same object describes to lower and retrieve a special, detachable catching substrate via an electrical cable winch directly on the pylon, so that the pylon itself here provides a kind of guide. However, the latter is not supported by securing elements, so that sea currents can here also be disruptive, and impede the harvesting process.
EP 1 466 523 A2 describes an extremely complicated design for bilaterally harvesting vertical netting substrates colonized by mollusks, for example. Two harvesting roller bands are here lowered on either side of the netting substrate on a vertical rail system. The band movement transports the colonized mollusks toward the water surface. The vertical rail system with the harvesting roller bands is secured to the side of a ship correspondingly positioned over the substrate. Lastly, described in GB 2 270 664 A is another vertical rail system with a moving carriage for the attachment of devices, which is arranged downward from the water line in the underwater region of a column of a footbridge. A boat can be connected with the rail system by means of a fender, so that depth-induced fluctuations in the boat level can be offset by vertically moving the fender on the rail system.